The party is considering moves to sideline the exams over concerns they do not stretch the brightest. Universities which complain about A-levels should "put their money where their mouth is" says higher education spokesman David Willetts.
The government recently made A-levels more stretching. The Lib Dems say exams are not just for the brightest. The Conservatives say universities can struggle to identify the brightest candidates because of the number of people scoring top grades. Last year a quarter of A-level papers were awarded A grades.
They have commissioned a review of the exams system from Sir Richard Sykes, the former rector of Imperial College London, which is due to be completed "later in the year". Mr Willetts suggested a body such as the Russell Group of leading universities could work together to set up an examining system to run alongside the current one.
"Universities are frustrated that A-level grades don't tell them what they need to know about potential students," Mr Willetts said. "Universities themselves can help tackle this problem if they set up exam boards to run A-levels along the lines they need.
"In fact that's historically where the exam boards came from and it could be a real contribution to improving standards in education." Only Cambridge now has links with an exam board.
It is behind the Pre-U qualification, which is an alternative to A-levels. A-levels themselves have already been overhauled by the government, in part to provide more "stretch" for brighter candidates.
Those scoring 90% or more will be awarded a new, top A* grade. The first of these will be awarded when the two-year courses are completed in 2010.
A spokeswoman for the Department for Children, Schools and Families said the A-level was still the most popular qualification for 16 to 18-year-olds.
"A-level standards are rising because teaching has improved and pupils are studying harder." Liberal Democrat spokesman for schools, David Laws said: "There's a concern that A-levels aren't rigorous enough and university involvement is welcome.
"However, we must not go back to the days of the 60s and 70s when school exams were designed around the needs of the minority rather than to serve the needs of all students."
Director General of the Russell Group, Dr Wendy Piatt, said: "Russell Group universities take a keen interest ensuring that UK qualifications are sufficiently robust and academically challenging so that students have the skills and knowledge to benefit most effectively from our courses.
"We have been actively engaged with A-level and other 14-19 curriculum reforms and make concerted efforts to identify the most effective ways of assessing potential and aptitude. "We are therefore willing to consider any way we can contribute to improving the means by which students are taught and assessed.
However, the costs and practical implications of designing and delivering school qualifications are significant and would have to be considered very carefully."